1. Field of the Invention
The invention relates to machine tool servo head structure and refers more specifically to servo head structure for electrical discharge machining equipment or the like including a ram movable within guides in a frame in accordance with the rotation of a shaft by a rotary servo electric hydraulic motor, which shaft is secured to the frame and is operably connected to the ram by cable means wrapped around the shaft and secured at its opposite ends to the opposite ends of the ram.
2. Description of the Prior Art
In the past, machine tool heads have generally been constructed of a ram movable in a guide actuated by a hydraulic piston and cylinder acting between the frame and guide. Also in the past, ball nut and screw structure secured between a frame and guide has been used to drive rams in machine tool heads. Such structure is both expensive and subject to an undesirable degree of backlash and inaccurate alignment. Wherein particularly precise ram movement has been accomplished in the past, the structures used therefor have been complicated and therefore expensive and often inefficient.